1. Field of the Invention
The present invention relates to an apparatus for generating remote plasma, and more particularly, to an apparatus for generating remote plasma that improves thin-film quality by reliably removing charges accumulated in a bias electrode.
2. Description of the Related Art
In recent years, as semiconductor devices shrink in size, it is required to perform plasma treatment under higher vacuum state for realizing patterns with high aspect ratio in dry etching, and filling a filling material into a hole with high aspect ratio in plasma chemical vapor deposition (plasma CVD) and atomic layer deposition (ALD).
In a typical parallel plate type apparatus for generating plasma, a substrate electrode with a substrate mounted thereon and an opposite electrode are installed in a vacuum chamber, and a high frequency voltage is then applied between the substrate electrode and the opposite electrode using high frequency power source for electrode. Resultantly, plasma is generated in the vacuum chamber.
However, according to the above configuration, the generated plasma does not uniformly react with the substrate mounted in the chamber, and plasma ions in the plasma have a direct impact on a wafer substrate, thereby causing the substrate to be damaged.
To solve such a limitation, positive ions in plasma are appropriately controlled by installing a DC bias electrode in a lower portion of a plasma generating unit, and thus it is possible to improve thin-film quality in some degree.
However, there is still a limitation in that positive ions created during the generation of plasma cannot be reliably trapped even using the above-described configuration.